Transcript Table of Contents - Regional School District 17

Chapter 36: Plant Nutrition
CHAPTER 36
Plant Nutrition
Chapter 36: Plant Nutrition
Chapter 36: Plant Nutrition
The Acquisition of Nutrients
Mineral Nutrients Essential to Plants
Soils and Plants
Chapter 36: Plant Nutrition
Chapter 36: Plant Nutrition
Nitrogen Fixation
Sulfur Metabolism
Heterotrophic and Carnivorous Seed Plants
Chapter 36: Plant Nutrition
The Acquisition of Nutrients
• Plants are photosynthetic autotrophs,
producing all the compounds they need
from carbon dioxide, water, and minerals.
• They obtain energy from sunlight, carbon
dioxide from the atmosphere, and nitrogencontaining ions and mineral nutrients from
soil.
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Chapter 36: Plant Nutrition
The Acquisition of Nutrients
• Plants explore their surroundings by
growing rather than by locomotion.
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Chapter 36: Plant Nutrition
Mineral Nutrients Essential to
Plants
• Plants require fourteen essential mineral
elements, all of which come from soil.
• Several essential elements fulfill multiple
roles. Review Table 36.1
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Chapter 36: Plant Nutrition
table 36-01.jpg
Table
36.1
Table 36.1
Chapter 36: Plant Nutrition
Mineral Nutrients Essential to
Plants
• The six mineral nutrients required in
substantial amounts are macronutrients
• The eight required in much smaller amounts
are micronutrients. Review Table 36.1
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Chapter 36: Plant Nutrition
Mineral Nutrients Essential to
Plants
• Deficiency symptoms suggest what essential
element a plant lacks. Review Table 36.2
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Chapter 36: Plant Nutrition
table 36-02.jpg
Table 36.2
Table 36.2
Chapter 36: Plant Nutrition
Mineral Nutrients Essential to
Plants
• Biologists discovered the essentiality of each
mineral nutrient by growing plants on
nutrient solutions lacking the test element.
Review Figure 36.2
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Chapter 36: Plant Nutrition
figure 36-02.jpg
Figure
36.2
Figure 36.2
Chapter 36: Plant Nutrition
Soils and Plants
• Soils have complex structure, with living and
nonliving components.
• They contain water, gases, and inorganic
and organic substances.
• They typically consist of two or three
horizontal zones called horizons. Review
Figures 36.3 and Table 36.3
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Chapter 36: Plant Nutrition
figure 36-03.jpg
Figure 36.3
Figure 36.3
Chapter 36: Plant Nutrition
table 36-03.jpg
Table 36.3
Table 36.3
Chapter 36: Plant Nutrition
Soils and Plants
• Soils form by mechanical and chemical
weathering of rock.
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Chapter 36: Plant Nutrition
Soils and Plants
• Plants obtain some mineral nutrients by ion
exchange between the soil solution and the
surface of clay particles. Review Figure 36.5
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Chapter 36: Plant Nutrition
figure 36-05.jpg
Figure
36.5
Figure 36.5
Chapter 36: Plant Nutrition
Soils and Plants
• Farmers use fertilizer to make up for
deficiencies in soil mineral nutrient content,
and apply lime to raise low soil pH.
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Chapter 36: Plant Nutrition
Soils and Plants
• Plants affect soils in various ways, helping
them form, adding material such as humus,
and removing nutrients.
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Chapter 36: Plant Nutrition
Nitrogen Fixation
• A few soil bacteria species are responsible
for almost all nitrogen fixation.
• Some live free in the soil; others live
symbiotically as bacteroids within plant
roots.
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Chapter 36: Plant Nutrition
Nitrogen Fixation
• In nitrogen fixation, nitrogen gas (N2) is
reduced to ammonia (NH3) or ammonium
ions (NH4+) in a reaction catalyzed by
nitrogenase. Review Figure 36.7
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Chapter 36: Plant Nutrition
figure 36-07a.jpg
Figure 36.7
– Part 1
Figure 36.7 – Part 1
Chapter 36: Plant Nutrition
figure 36-07b.jpg
Figure 36.7
– Part 2
Figure 36.7 – Part 2
Chapter 36: Plant Nutrition
Nitrogen Fixation
• Nitrogenase requires anaerobic conditions,
but bacteroids in root nodules require
oxygen for respiration.
• Leghemoglobin helps maintain the oxygen
supply to bacteroids.
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Chapter 36: Plant Nutrition
Nitrogen Fixation
• Nodule formation requires an interaction
between the root system of a legume and
Rhizobium bacteria. Review Figure 36.8
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Chapter 36: Plant Nutrition
figure 36-08a.jpg
Figure 36.8
– Part 1
Figure 36.8 – Part 1
Chapter 36: Plant Nutrition
figure 36-08b.jpg
Figure 36.8
– Part 2
Figure 36.8 – Part 2
Chapter 36: Plant Nutrition
Nitrogen Fixation
• Nitrogen-fixing bacteria reduce atmospheric
N2 to ammonia, but most plants take up
both ammonium and nitrate ions.
• Nitrifying bacteria oxidize ammonia to
nitrate.
• Plants take up nitrate and reduce it back to
ammonia, something animals are incapable
of doing. Review Figure 36.9
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Chapter 36: Plant Nutrition
Nitrogen Fixation
• Denitrifying bacteria return N2 to the
atmosphere, completing the biological
nitrogen cycle. Review Figure 36.9
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Chapter 36: Plant Nutrition
figure 36-09.jpg
Figure 36.9
Figure 36.9
Chapter 36: Plant Nutrition
Sulfur Metabolism
• Plants take up sulfate ions and reduce them,
forming cysteine and methionine.
• Cysteine is the major precursor for other
sulfur-containing compounds in plants and
in animals, which must obtain organic sulfur
from plants.
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Chapter 36: Plant Nutrition
Heterotrophic and
Carnivorous Seed Plants
• A few heterotrophic plants are parasitic on
other plants.
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Chapter 36: Plant Nutrition
Heterotrophic and
Carnivorous Seed Plants
• Carnivorous plants are autotrophs that
supplement their nitrogen supply by feeding
on insects.
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